Many factors can influence the voice levels that talkers choose to use when they initiate conversations in noisy environments, including the desire to be understood clearly, the desire to communicate privately, and the distorted perception of the background noise and of their own voices that can occur when hearing protection devices are worn. In this study, we examined the impact that two different kinds of earplugs and four levels of room noise had on the voice levels of talkers who were asked to privately communicate short verbal messages to a nearby acoustic manikin. Frozen noise samples were used for the room noise, which allowed the speech samples recorded by the manikin to be extracted from the noise by direct waveform subtraction. The results show that talkers wearing earplugs consistently use lower voice levels in noise than they do when not wearing earplugs, even when the earplugs produce relatively little attenuation. This highlights the important impact that earplugrelated distortions in the perception of ones own voice (which are commonly referred to as the occlusion effect) can have on the effectiveness of speech communication in noise.

Index Terms: shouted speech, hearing protection, occlusion effect